Network requested packet data protocol context activation

ABSTRACT

A packet switched (PS) core network (CN) supporting several quality of services levels, comprising at least a serving node (SGSN), a gateway node (GGSN), a home location register (HLR), a short message service gateway and interworking unit (SMS-GMSC, SMS-IWMSC), charging gateway functionality (CGF), and a public data network (PDN) comprising an application server (AS). The core network is adapted for carrying out a packet data protocol (PDP) context activation in which a PDP address is assigned to a mobile station and in which a given quality of service is assigned through the network in a communication session between the mobile station and the application processor in question, whereby the application server (AS) initiates a context activation in which the QoS is seeked altered for the mobile station.

FIELD OF THE INVENTION

The present invention relates to a method for a packet data andtelecommunication systems, comprising wireless and wirelinesub-networks. The invention concerns in particular a method for a PDP(Packet Data Protocol) context activation procedure in a core networkbased on GSM (Global System for Mobile telephony), GPRS (General Packetradio System) and UMTS (Universal Mobile Telephony System) elements.

BACKGROUND OF THE INVENTION

According to the 3'rd generation partnership project (3GPP) technicalspecification, 3G TS 23.060 v3.4.0 (2000-07) a common packet domain CoreNetwork is used for both GSM and UMTS. Such a system has been shown inFIG. 1. A similar system has been shown in WO99/05828.

The above Core Network provides packet-switched (PS) services and isdesigned to support several quality of services levels in order to allowefficient transfer of non real-time traffic (e.g., intermittent andbursty data transfers, occasional transmission of large volumes of data)and real-time traffic (e.g., voice, video). One class of quality ofservice pertains to a low throughput and a low delay; another classpertains to higher throughput and longer delay and a further classpertains to relatively long delays and high throughput.

Applications based on standard data protocols and SMS are supported, andinterworking is defined with IP networks. Charging is rendered flexibleand allows Internet Service Providers to bill according to the amount ofdata transferred, the QoS supported, and the duration of the connection.

Each PLMN has two access points, the radio interface (labelled Um in GSMand Uu in UMTS) used for mobile access and the R reference point usedfor origination or reception of messages.

An interface differs from a reference point in that an interface isdefined where specific information is exchanged and needs to be fullyrecognised. There is an inter PLMN interface called Gp that connects twoindependent packet domain networks for message exchange. There is also aPLMN to fixed network (typically a packet data network) reference pointcalled Gi.

There may be more than a single network interface to several differentpacket data (or other) networks. These networks may both differ inownership as well as in communications protocol (e.g., TCP/IP etc.). Thenetwork operator should define and negotiate interconnect with eachexternal (PDN or other) network.

Network interworking is required whenever a packet domain PLMN and anyother network are involved in the execution of a service request. Withreference to FIG. 1, interworking takes place through the Gi referencepoint and the Gp interface.

The internal mechanism for conveying the PDP (Packet Data Protocol) PDU(Packet Data Unit) through the PLMN is managed by the PLMN networkoperator and is not apparent to the data user. The use of the packetdomain data service may have an impact on and increase the transfer timenormally found for a message when communicated through a fixed packetdata network.

The packet domain supports interworking with networks based on theInternet protocol (IP). The packet domain may provide compression of theTCP/IP header when an IP datagram is used within the context of a TCPconnection.

The packet domain PLMN service is an IP domain, and mobile terminalsoffered service by a service provider may be globally addressablethrough the network operator's addressing scheme.

A GPRS Support Node (GSN) contains functionality required to supportGPRS functionality for GSM and/or UMTS. In one PLMN, there may be morethan one GSN.

The Gateway GPRS Support Node (GGSN) is the node that is accessed by thepacket data network due to evaluation of the PDP address. It containsrouting information for PS-attached users. The routing information isused to tunnel N-PDUs to the MS's current point of attachment, i.e., theServing GPRS Support Node. The GGSN may request location informationfrom the HLR via the optional Gc interface. The GGSN is the first pointof PDN interconnection with a GSM PLMN supporting GPRS (i.e., the Gireference point is supported by the GGSN). GGSN functionality is commonfor GSM and UMTS.

The Serving GPRS Support Node (SGSN) is the node that is serving the MS.The SGSN supports GPRS for GSM (i.e., the Gb interface is supported bythe SGSN) and/or UMTS (i.e., the lu interface is supported by the SGSN).

In order to access the PS services, an MS shall first make its presenceknown to the network by performing a GPRS Attach. This makes the MSavailable for SMS over PS, paging via the SGSN, and notification ofincoming PS data. According to the Attach, the IMSI (InternationalMobile Subscription Identity) of the mobile station (MS) is mapped toone or more packet data protocol addresses (PDP).

At PS Attach, the SGSN establishes a mobility management contextcontaining information pertaining to e.g., mobility and security for theMS.

In order to send and receive PS data, the MS shall activate the PacketData Protocol context that it wants to use. This operation makes the MSknown in the corresponding GGSN, and interworking with external datanetworks can commence.

At PDP Context Activation, the SGSN establishes a PDP context, to beused for routing purposes, with the GGSN that the subscriber will beusing.

The SGSN and GGSN functionalities may be combined in the same physicalnode, or they may reside in different physical nodes. SGSN and GGSNcontain IP or other (operator's selection, e.g., ATM-SVC) routingfunctionality, and they may be interconnected with IP routers. In UMTS,the SGSN and RNC may be interconnected with one or more IP routers. WhenSGSN and GGSN are in different PLMNs, they are interconnected via the Gpinterface. The Gp interface provides the functionality of the Gninterface, plus security functionality required for inter-PLMNcommunication. The security functionality is based on mutual agreementsbetween operators.

The SGSN may send location information to the MSC/VLR via the optionalGs interface. The SGSN may receive paging requests from the MSC/VLR viathe Gs interface.

According to the PDP context activation, a network bearer (IP)communication between the mobile station and the Internet serviceprovider (ISP) is established. Moreover, a given class of Quality ofService class is assigned for the communication to be performed.

The Charging Gateway Functionality (CGF) collects charging records fromSGSNs and GGSNs. The HLR (Home Location Register) contains GSM and UMTSsubscriber information. The HLR stores the IMSI (International MobileSubscription Identity) and maps the IMSI to one or more packet dataprotocol addresses (PDP) and maps each PDP address to one or moreGGSN's.

The SMS-GMSCs and SMS-IWMSCs support SMS transmission via the SGSN.Optionally, the MSC/VLR can be enhanced for more-efficient co-ordinationof packet-switched and circuit-switched services and functionality:e.g., combined GPRS and non-GPRS location updates.

User data is transferred transparently between the MS and the externaldata networks with a method known as encapsulation and tunnelling: datapackets are equipped with PS-specific protocol information andtransferred between the MS and the GGSN. This transparent transfermethod lessens the requirement for the PLMN to interpret external dataprotocols, and it enables easy introduction of additional interworkingprotocols in the future.

An Application Server (AS) is connected to the Packet Data Network (PDN)for providing information. The application server may be owned by anInternet Service Provider (ISP), the PLMN, or an independent company.

MS Initiated PDP Context Activation

We shall now revert to the PDP context activation procedure.

In FIG. 2, a sequence diagram relating to the Mobile Station initiatedcontext activation procedure has been shown.

-   -   1) The MS sends an Activate PDP Context Request (NSAPI, TI, PDP        Type, PDP Address, Access Point Name, QoS Requested, PDP        Configuration Options) message to the SGSN. The MS may use        Access Point Name to select a reference point to a certain        external network and/or to select a service. QoS Requested        indicates the desired QoS profile.    -   3) In UMTS, RAB (Radio Bearer) set-up is done by the RAB        Assignment procedure.    -   4) If BSS trace is activated, then the SGSN shall send an Invoke        Trace (Trace Reference, Trace Type, Trigger Id) message to the        BSS or UTRAN. Trace Reference and Trace Type are copied from the        trace information received from the HLR. Thereby, the location        of the mobile station can be established.    -   5a) The SGSN validates the Activate PDP Context Request using        PDP Type (optional), PDP Address (optional), and Access Point        Name (optional) provided by the MS and the PDP context        subscription records        -   The SGSN may restrict the requested QoS attributes given its            capabilities, the current load, and the subscribed QoS            profile.        -   The SGSN sends a Create PDP Context Request (PDP Type, PDP            Address, Access Point Name, QoS Negotiated, TEID, NSAPI,            MSISDN, Selection Mode, Charging Characteristics, Trace            Reference, Trace Type, Trigger Id, PDP Configuration            Options) message to the affected GGSN    -   5b) The GGSN creates a new entry in its PDP context table and        generates a Charging Id. The new entry allows the GGSN to route        PDP PDUs between the SGSN and the external PDP network, and to        start charging. The GGSN then returns a Create PDP Context        Response (TEID, PDP Address, PDP Configuration Options, QoS        Negotiated, Charging Id, Cause) message to the SGSN.    -   6) The SGSN selects Radio Priority and Packet Flow Id based on        QoS Negotiated, and returns an Activate PDP Context Accept (PDP        Type, PDP Address, TI, QoS Negotiated, Radio Priority, Packet        Flow Id, PDP Configuration Options) message to the MS. The SGSN        is now able to route PDP PDUs between the GGSN and the MS, and        to start charging.    -   7) Now, a packet data session is open between the Mobile Station        (MS) and the Application Server (AS).

For each PDP Address, a different quality of service (QoS) profile maybe requested. For example, some PDP addresses may be associated withE-mail that can tolerate lengthy response times. Other applicationscannot tolerate delay and demand a very high level of throughput,interactive applications being one example. These different requirementsare reflected in the QoS profile. If a QoS profile requirement is beyondthe capabilities of a PLMN, the PLMN negotiates the QoS profile as closeas possible to the requested QoS profile. The MS either accepts thenegotiated QoS profile, or deactivates the PDP context.

AS Initiated PDP Context Activation

The scenario for setting up a session initiated by the an externalapplication server has been illustrated by the sequence diagram shown inFIG. 3:

The Network-Requested PDP Context Activation procedure allows the GGSNto initiate the activation of a PDP context. When receiving a PDP PDUthe GGSN checks if a PDP context is established for that PDP address. Ifno PDP context has been previously established the GGSN may try todeliver the PDP PDU by initiating the Network-Requested PDP ContextActivation procedure.

-   -   1) When receiving a PDP PDU the GGSN determines if the        Network-Requested PDP Context Activation procedure has to be        initiated. The GGSN may store subsequent PDP PDU's received for        the same PDP address.    -   2a) The GGSN may send a Send Routing Information for GPRS (IMSI)        message to the HLR.    -   2b) If the HLR determines that the request can be served, it        returns a Send Routing Information for GPRS Ack (IMSI, SGSN        Address, Mobile Station Not Reachable Reason) message to the        GGSN.    -   3a) The GGSN shall send a PDU Notification Request (IMSI, PDP        Type, PDP Address, APN) message to the SGSN indicated by the        HLR.    -   3b)The SGSN returns a PDU Notification Response (Cause) message        to the GGSN in order to acknowledge that it shall request the MS        to activate the PDP context indicated with PDP Address.    -   4) The SGSN sends a Request PDP Context Activation (TI, PDP        Type, PDP Address, APN) message to request the MS to activate        the indicated PDP context.    -   5) The PDP context is activated with the PDP Context Activation        procedure.

As mentioned above, it is possible that the mobile station needs adifferent QoS from what was initially needed. In order to modify theQoS, the mobile station may take one of the following steps:

-   -   The MS initiates a new primary PDP Context.    -   There is an active PDP context, but it is established with        insufficient bandwidth, QoS. The MS may trigger a PDP Context        Modification.    -   There is an active PDP context, but it is established with        insufficient bandwidth, QoS. The MS may trigger a secondary PDP        Context Modification.

The two latter procedures shall be dealt with below.

In FIG. 4, a procedure of the mobile station modifying the PDP contextis shown in which the following steps are carried out:

-   -   1) The MS sends a Modify PDP Context Request (TI, QoS Requested,        TFT) message to the SGSN. Either QoS Requested or TFT or both        may be included. QoS Requested indicates the desired QoS        profile, while TFT indicates the TFT that is to be added or        modified or deleted from the PDP context.    -   2) The SGSN may restrict the desired QoS profile given its        capabilities, the current load, and the subscribed QoS profile.        The SGSN sends an Update PDP Context Request (TEID, NSAPI, QoS        Negotiated, TFT) message to the GGSN. If QoS Negotiated and/or        TFT received from the SGSN is incompatible with the PDP context        being modified (e.g., TFT contains inconsistent packet filters),        then the GGSN rejects the Update PDP Context Request. The        compatible QoS profiles are configured by the GGSN operator.    -   3) The GGSN may further restrict QoS Negotiated given its        capabilities and the current load. The GGSN stores QoS        Negotiated, stores, modifies, or deletes TFT of that PDP context        as indicated in TFT, and returns an Update PDP Context Response        (TEID, QoS Negotiated) message.    -   4) In UMTS, radio access bearer modification may be performed by        the RAB Assignment procedure.    -   5) The SGSN selects Radio Priority and Packet Flow Id based on        QoS Negotiated, and returns a Modify PDP Context Accept (TI, QoS        Negotiated, Radio Priority, Packet Flow Id) message to the MS.

In FIG. 5, a procedure for activation of a secondary PDP context hasbeen shown in which the following steps are carried out:

-   -   1) The MS sends an Activate Secondary PDP Context Request        (Linked TI, NSAPI, TI, QoS Requested, TFT) message to the SGSN.        Linked TI indicates the TI value assigned to any one of the        already activated PDP contexts for this PDP address and APN. QoS        Requested indicates the desired QoS profile. TFT is sent        transparently through the SGSN to the GGSN to enable packet        classification for downlink data transfer. TI and NSAPI contain        values not used by any other activated PDP context.    -   2) In GSM, security functions may be executed.    -   3) In UMTS, RAB set-up is done by the RAB Assignment procedure.    -   4a) The SGSN validates the Activate Secondary PDP Context        Request using the TI indicated by Linked TI. The same GGSN        address is used by the SGSN as for the already-activated PDP        context(s) for that TI and PDP address.        -   The SGSN and GGSN may restrict and negotiate the requested            QoS. The SGSN sends a Create PDP Context Request (QoS            Negotiated, TEID, NSAPI, Primary NSAPI, TFT) message to the            affected GGSN. Primary NSAPI indicates the NSAPI value            assigned to any one of the already activated PDP contexts            for this PDP address and APN. TFT is included only if            received in the Activate Secondary PDP Context Request            message. The GGSN uses the same external network as used by            the already-activated PDP context(s) for that PDP address,            generates a new entry in its PDP context table, and stores            the TFT. The new entry allows the GGSN to route PDP PDUs via            different GTP tunnels between the SGSN and the external PDP            network.    -   4b) The GGSN returns a Create PDP Context Response (TEID, QoS        Negotiated, Cause) message to the SGSN.

In GSM, BSS packet flow context procedures may be executed.

-   -   5) The SGSN selects Radio Priority and Packet Flow Id based on        QoS Negotiated, and returns an Activate Secondary PDP Context        Accept (TI, QoS Negotiated, Radio Priority, Packet Flow Id)        message to the MS. The SGSN is now able to route PDP PDUs        between the GGSN and the MS via different GTP tunnels and        possibly different LLC links.        Push Services

One type of service which can be accomplished in the above system isso-called “push” services, that is, an Application Server (AS) takes theinitiative to render information, such as stock quotes, news orcommercials, available to one or a plurality of mobile terminals.

SUMMARY OF THE INVENTION

It is a first object of the present invention to set forth a method foreffectively assigning a given quality of service to a server initiatedcommunication session.

It is another object of the present invention to communicate aparticular level of desired QoS from an application server connected toa public data network to a mobile station being served by a packetswitched core network. In accordance with one aspect of the presentinvention, the application server communicates the QoS data directly tothe mobile station using a Short Message Service. In another aspect ofthe present invention, the application server communicates the QoS datawithin a Push Request transmitted to a gateway node (GGSN) associatedwith the serving core network. In yet another aspect of the presentinvention, the application server communicates the QoS data within aProtocol Data Unit (PDU) transmitted to a gateway node (GGSN) associatedwith the serving core network. The mobile station then establishes acommunication session with the application server using the requestedQoS level.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a prior art common packet domain core network for GSM andUMTS use,

FIG. 2 discloses a sequence diagram for a prior art context activationprocedure initiated by a mobile station,

FIG. 3 discloses a sequence diagram for a prior art context activationprocedure initiated by an application server,

FIG. 4 discloses a sequence diagram for a prior art procedure initiatedby the mobile station for modifying the PDP context,

FIG. 5 discloses a sequence diagram for a prior art procedure initiatedby the mobile station for a secondary modification of the PDP context,

FIG. 6 discloses a sequence diagram for a first embodiment of a contextactivation procedure initiated by an application server according to theinvention. The MS is contacted with an SMS message, including theQoS(R), which in turn triggers the MS to start the PDP ContextActivation procedure,

FIG. 7 discloses a sequence diagram for a second embodiment of a contextactivation procedure initiated by an application server according to theinvention. The GGSN receives a push request, including the QoS(R), fromthe AS,

FIG. 8 discloses a sequence diagram for a third embodiment of a contextactivation procedure initiated by an application server according to theinvention. The GGSN receives an incoming PDU from which the GGSN candeduce the QoS(R) (e.g., mapping of the ds-byte of the IP-header to thedefined corresponding QoS(R)),

FIG. 9 discloses a sequence diagram for a fourth embodiment of a contextactivation procedure initiated by an application server according to theinvention. The MS is contacted with an SMS message, including theQoS(R). The MS chooses to trigger the PDP Context Modificationprocedure, and

FIG. 10 discloses a sequence diagram for a fifth embodiment of a contextactivation procedure initiated by an application server according to theinvention. The MS is contacted with an SMS message, including theQoS(R). The MS chooses to initiate a secondary PDP Context.

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

The scenario for setting up a session initiated by an externalapplication server, when QoS has been included in the communicationbetween the AS and the MS (by SMS), is illustrated by the sequencediagram shown in FIG. 6:

-   -   1) A push request is sent to the MS through an SMS message,        asking for a session with a certain QoS, the QoS(R). The MS does        not have an active PDP Context. Delivery of the SMS involves the        nodes SC, SMS-GMSC, HLR and SGSN.    -   2) The MS sends an Activate PDP Context Request (NSAPI, TI, PDP        Type, PDP Address, Access Point Name, QoS Requested, PDP        Configuration Options) message to the SGSN. The MS may use        Access Point Name to select a reference point to a certain        external network and/or to select a service. QoS Requested        indicates the desired QoS profile.    -   3) In UMTS, RAB (Radio Bearer) set-up is done by the RAB        Assignment procedure.    -   4) If BSS trace is activated, then the SGSN shall send an Invoke        Trace (Trace Reference, Trace Type, Trigger Id, OMC Identity)        message to the BSS or UTRAN. Trace Reference, and Trace Type are        copied from the trace information received from the HLR or OMC.    -   5a) The SGSN validates the Activate PDP Context Request using        PDP Type (optional), PDP Address (optional), and Access Point        Name (optional) provided by the MS and the PDP context        subscription records        -   The SGSN may restrict the requested QoS attributes given its            capabilities the current load, and the subscribed QoS            profile.        -   The SGSN sends a Create PDP Context Request (PDP Type, PDP            Address, Access Point Name, QoS Negotiated, TEID, NSAPI,            MSISDN, Selection Mode, Charging Characteristics, Trace            Reference, Trace Type, Trigger Id, OMC Identity, PDP            Configuration Options) message to the affected GGSN        -   The GGSN creates a new entry in its PDP context table and            generates a Charging Id. The new entry allows the GGSN to            route PDP PDUs between the SGSN and the external PDP            network, and to start charging.    -   5b) The GGSN then returns a Create PDP Context Response (TEID,        PDP Address, PDP Configuration Options, QoS Negotiated, Charging        Id, Cause) message to the SGSN.    -   6) The SGSN selects Radio Priority and Packet Flow Id based on        QoS Negotiated, and returns an Activate PDP Context Accept (PDP        Type, PDP Address, TI, QoS Negotiated, Radio Priority, Packet        Flow Id, PDP Configuration Options) message to the MS. The SGSN        is now able to route PDP PDUs between the GGSN and the MS, and        to start charging.    -   7) Now, a packet data session is open between the Mobile Station        (MS) and the Application Server (AS).

It follows from the above procedure, that the service of qualityrequested by the application server is communicated in the initialrequest towards the mobile station.

Second Embodiment

The scenario for setting up a session initiated by an externalapplication server, when QoS has been included in the communicationbetween the AS and the GGSN (by some protocol), is illustrated by thesequence diagram shown in FIG. 7 (only the new points are mentionedhere)

-   -   1) The AS sends a push request to the GGSN, asking the GGSN to        located the MS and request it to activate a PDP context with a        certain QoS, the QoS(R).    -   2a) The GGSN may send a Send Routing Information for GPRS (IMSI)        message to the HLR.    -   2b) If the HLR determines that the request can be served, it        returns a Send Routing Information for GPRS Ack (IMSI, SGSN        Address, Mobile Station Not Reachable Reason) message to the        GGSN.    -   3a) The GGSN shall send a PDU Notification Request (IMSI, PDP        Type, PDP Address, APN, QoS(R)) message to the SGSN indicated by        the HLR.    -   3b) The SGSN responds with PDU Notification.    -   4) The SGSN sends a Request PDP Context Activation (TI, PDP        Type, PDP Address, APN, QoS(R)) message to request the MS to        activate the indicated PDP context.    -   5) PDP Context Activation as in FIG. 2.    -   6) Now, a packet data session is open between the Mobile Station        (MS) and the Application Server (AS).

Third Embodiment

The scenario for setting up a session initiated by an externalapplication server, when QoS is deduced from the incoming PDP PDU sentfrom the AS to the GGSN, is illustrated by the sequence diagram shown inFIG. 8.

-   -   1) A PDP PDU is received in the GGSN. The GGSN reads the QoS        information in the packet, e.g., the ds-byte of the IP header        (shown in the figure), and maps it to the appropriate QoS(R).    -   2a) The GGSN may send a Send Routing Information for GPRS (IMSI)        message to the HLR.    -   2b) If the HLR determines that the request can be served, it        returns a Send Routing Information for GPRS Ack (IMSI, SGSN        Address, Mobile Station Not Reachable Reason) message to the        GGSN.    -   3a) The GGSN shall send a PDU Notification Request (IMSI, PDP        Type, PDP Address, APN, QoS(R)) message to the SGSN indicated by        the HLR.    -   3b) The SGSN responds with PDU Notification.    -   4) The SGSN sends a Request PDP Context Activation (TI, PDP        Type, PDP Address, APN, QoS(R)) message to request the MS to        activate the indicated PDP context.    -   5) PDP Context Activation as in FIG. 2.    -   6) Now, a packet data session is open between the Mobile Station        (MS) and the Application Server (AS).

Fourth Embodiment

The scenario for modifying an active session, initiated by an externalapplication server, when QoS has been included in the communicationbetween the AS and the MS (by SMS), is illustrated by the sequencediagram shown in FIG. 9:

-   -   1) A push request is sent to the MS through an SMS message,        asking for a session with a certain QoS, the QoS(R). The MS has        an active PDP Context associated with a QoS class. Delivery of        the SMS involves the nodes SC, SMS-GMSC, HLR and SGSN.    -   2) If the QoS of the active PDP Context is not sufficient, the        MS may send a Modify PDP Context Request (TI, QoS Requested,        TFT) message to the SGSN. Either QoS Requested or TFT or both        may be included. QoS Requested indicates the desired QoS        profile, while TFT indicates the TFT that is to be added,        modified, or deleted from the PDP context.    -   3) The SGSN may restrict the desired QoS profile given its        capabilities, the current load, and the subscribed QoS profile.        The SGSN sends an Update PDP Context Request (TEID, NSAPI, QoS        Negotiated, TFT) message to the GGSN. If QoS Negotiated and/or        TFT received from the SGSN is incompatible with the PDP context        being modified (e.g., TFT contains inconsistent packet filters),        then the GGSN rejects the Update PDP Context Request. The        compatible QoS profiles are configured by the GGSN operator.    -   4) The GGSN may further restrict QoS Negotiated given its        capabilities and the current load. The GGSN stores QoS        Negotiated, stores, modifies, or deletes TFT of that PDP context        as indicated in TFT, and returns an Update PDP Context Response        (TEID, QoS Negotiated) message.    -   5) In UMTS, radio access bearer modification may be performed by        the RAB Assignment procedure.    -   6) The SGSN selects Radio Priority and Packet Flow Id based on        QoS Negotiated, and returns a Modify PDP Context Accept (TI, QoS        Negotiated, Radio Priority, Packet Flow Id) message to the MS.    -   7) Now, a packet data session is open between the Mobile Station        (MS) and the Application Server (AS).

Fifth Embodiment

The scenario for setting up a session initiated by an externalapplication server, when QoS has been included in the communicationbetween the AS and the MS (by SMS), is illustrated by the sequencediagram shown in FIG. 10:

-   -   1) A push request is sent to the MS through an SMS message,        asking for a session with a certain QoS, the QoS(R). The MS has        an active PDP Context associated with a QoS class. Delivery of        the SMS involves the nodes SC, SMS-GMSC, HLR and SGSN.    -   2) If the QoS of the active PDP Context is not sufficient, the        MS may send an Activate Secondary PDP Context Request (Linked        TI, NSAPI, TI, QoS Requested, TFT) message to the SGSN. Linked        TI indicates the TI value assigned to any one of the already        activated PDP contexts for this PDP address and APN. QoS        Requested indicates the desired QoS profile. TFT is sent        transparently through the SGSN to the GGSN to enable packet        classification for downlink data transfer. TI and NSAPI contain        values not used by any other activated PDP context.        -   In GSM, security functions may be executed.    -   3) In UMTS, RAB set-up is done by the RAB Assignment procedure.    -   4a) The SGSN validates the Activate Secondary PDP Context        Request using the TI indicated by Linked TI. The same GGSN        address is used by the SGSN as for the already-activated PDP        context(s) for that TI and PDP address.        -   The SGSN and GGSN may restrict and negotiate the requested            QoS. The SGSN sends a Create PDP Context Request (QoS            Negotiated, TEID, NSAPI, Primary NSAPI, TFT) message to the            affected GGSN. Primary NSAPI indicates the NSAPI value            assigned to any one of the already activated PDP contexts            for this PDP address and APN. TFT is included only if            received in the Activate Secondary PDP Context Request            message. The GGSN uses the same external network as used by            the already-activated PDP context(s) for that PDP address,            generates a new entry in its PDP context table, and stores            the TFT. The new entry allows the GGSN to route PDP PDUs via            different GTP tunnels between the SGSN and the external PDP            network.    -   4b) The GGSN returns a Create PDP Context Response (TEID, QoS        Negotiated, Cause) message to the SGSN.        -   In GSM, BSS packet flow context procedures may be executed.    -   5) The SGSN selects Radio Priority and Packet Flow Id based on        QoS Negotiated, and returns an Activate Secondary PDP Context        Accept (TI, QoS Negotiated, Radio Priority, Packet Flow Id)        message to the MS. The SGSN is now able to route PDP PDUs        between the GGSN and the MS via different GTP tunnels and        possibly different LLC links.    -   6) Now, a packet data session is open between the Mobile Station        (MS) and the Application Server (AS).

As appears from the above exemplary embodiments, the invention providesfor a number of advantages.

By making it possible to send the requested QoS class in connection withthe Network Requested PDP Context process, the establishment of a PDPsession with an appropriate bandwidth/reliability is facilitated. Apossible PDP Context Modification procedure in direct connection to thePDP session initiation is avoided, thus decreasing the amount ofsignalling required for the Network Requested PDP Context Activationprocedure.

According to invention, the Mobile Station (MS) is given an opportunityto choose to set up an appropriate session. This will positively affectat least the network and the mobile station capabilities. Hence,procedures that are more flexible can be built into the mobile station.

Abbreviations AS Application Server APN Access Point Name ATMAsynchronous Transfer Mode ATM-SVC ATM-Switched Virtual Circuit BSS BaseStation System CGF Charging Gateway Functionality GGSN Gateway GPRSServing Node GPRS General Packet Radio System GSM Global System forMobile telephony HLR Home Location Register IMSI International MobileSubscriber Identity IP Internet Protocol MS Mobile Station MSC-VLRMobile Switching Centre MSISDN MS International ISDN Number NSAPINetwork layer Service Access Point Identifier PDN Packet Data NetworkPDP Packet Data Protocol, e.g., IP PDU Protocol Data Unit PLMN PublicLand Mobile Network PS Packet Switched QoS Quality of Service RAB RadioAccess Bearer SGSN Serving GPRS Support Node SM Short Message SMS ShortMessage Service SM-SC Short Message Service Centre SMS-GMSC ShortMessage Service Gateway MSC SMS-IWMSC Short Message Service InterworkingMSC TCP Transmission Control Protocol TE Terminal Equipment TEID TunnelEndpoint IDentifier TI Transaction Identifier UMTS Universal MobileTelephony System UTRAN UMTS Terrestrial Radio Access Network Ga Chargingdata collection interface between a CDR transmitting unit (e.g., an SGSNor a GGSN) and a CDR receiving functionality (a CGF). Gb Interfacebetween an SGSN and a BSS. Gc Interface between a GGSN and an HLR. GdInterface between a SMS-GMSC and an SGSN, and between a SMS-IWMSC and anSGSN. Gf Interface between an SGSN and an EIR. Gi Reference pointbetween GPRS and an external packet data network. Gn Interface betweentwo GSNs within the same PLMN. Gp Interface between two GSNs indifferent PLMNs. The Gp interface allows support of GPRS networkservices across areas served by the co- operating GPRS PLMNs. GrInterface between an SGSN and an HLR. Gs Interface between an SGSN andan MSC/VLR. Iu Interface between the RNS and the core network. It isaiso considered as a reference point. R Reference point between anon-ISDN compatible TE and MT. Typically this reference point supports astandard serial interface. Um Interface between the mobile station (MS)and the GSM fixed network part. The Um interface is the GSM networkinterface for providing GPRS services over the radio to the MS. The MTpart of the MS is used to access the GPRS services in GSM through thisinterface. Uu Interface between the mobile station (MS) and the UMTSfixed network part. The Uu interface is the UMTS network interface forproviding GPRS services over the radio to the MS. The MT part of the MSis used to access the GPRS services in UMTS through this interface.

1. A method for communicating in a packet switched core networksupporting several quality of service (QoS) levels, the core networkincluding at least a serving GRPS (General Packet Radio System) supportnode (SGSN), a gateway GPRS serving node (GGSN), a home locationregister (HLR), a short message service gateway mobile switching center(SMS-GMSC) and an interworking unit mobile switching center (SMS-IWMSC),charging gateway functionality (CGF), and a public data network (PDN)comprising an application server, the core network being adapted forcarrying out at least a mobile initiated packet data protocol (PDP)context activation in which a PDP address is assigned to a mobilestation and in which a given QoS is assigned through the network in acommunication session between the mobile station and the applicationserver, wherein each given QoS defines a level of performanceexpectation on the network by the mobile station, said method comprisingthe steps of: initiating a PDP context activation by the applicationserver, in which the application server sends by SMS message a requestedQoS class to the mobile station; receiving from said mobile station aPDP context activation request sent in response to said SMS messageincluding a requested QoS class; establishing the communication sessionassociated with the requested QoS class between said mobile station andthe application server using the SGSN and the GGSN within the corenetwork; wherein the QoS class is defined by throughput and time delayin the transfer of non-real and real-time traffic; and wherein the PDPcontext activation request is an activate secondary PDP context requestwith the requested QoS class.
 2. Method according to claim 1, whereinthe PDP context activation request is a PDP activate context requestwith the requested QoS class.
 3. Method according to claim 1, whereinthe PDP context activation request is a modify PDP context request withthe requested QoS class.
 4. Method according to claim 1, wherein saidSMS message containing the requested QoS class is transmitted from saidapplication server to said mobile station using said short messageservice gateway mobile switching center (SMS-GMSC) and said interworkingunit mobile switching center (SMS-IWMSC) within said core network. 5.Method according to claim 1 wherein the QoS class defines an expectedperformance level of data transfer or traffic priority within thenetwork for a specified mobile station.
 6. Method according to claim 1,wherein the application server sends the requested QoS class with arequest for the PDP context activation.